Methods for producing and purifying 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers and polycarbonates derived therefrom

ABSTRACT

Disclosed herein is a method for producing a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The method comprises forming a reaction mixture comprising at least one substituted or unsubstituted phenolphthalein, at least one substituted or unsubstituted primary hydrocarbyl amine, and an acid catalyst; and heating the reaction mixture to a temperature of less than 180° C. to remove a distillate comprising water and form a crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product; where the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:  
                 
 
where R 1  is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R 2  is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen.

BACKGROUND

The present disclosure generally relates to a method for producing andpurifying 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers,and polycarbonates as well as other polymers derived utilizing themonomers.

Phenolphthalein has been used as an aromatic dihydroxy compound monomerfor preparing polycarbonates, which are generally characterized withexcellent ductility and high glass transition temperatures. Certainderivatives of phenolphthalein have also been used as aromatic dihydroxycompound monomers to prepare polycarbonate resins as well as polyarylateresins. For example, polycarbonate homopolymers have been prepared by aninterfacial polycondensation method using phosgene and monomers such as3,3-bis(4-hydroxyphenyl)phthalimidine and2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (hereinafter sometimesreferred to as “para,para-PPPBP”).

Lin and Pearce (Journal of Polymer Science: Polymer Chemistry Edition,(1981) Vol. 19, pp. 2659 - 2670) reported the synthesis of para,para-PPPBP for preparing polycarbonates and other polymers by refluxingphenolphthalein and aniline hydrochloride in aniline for 6 hours,followed by recrystallization from ethanol. During this reaction, sideproducts are created which, if not removed, can result in para,para-PPPBP having an unacceptable purity for use as a monomer or as acomonomer. The undesirable side products or impurities generally includeboth inorganic and organic species. With regard to the manufacture ofpolycarbonate, the impurities can hinder polymerization and result inlow weight average molecular weight polycarbonates, example, less thanabout 22,000 Daltons for melt polymerization and less than about 50,000Daltons for an interfacial polymerization that exhibit undesirablephysical properties, such as increased brittleness, that is, poorductility properties. Furthermore, the impurities in the para,para-PPPBP monomer include, for example, trace (parts per million)levels of phenolphthalein or phenolphthalein residues that canundesirably produce discoloration in the polycarbonates and otherpolymers derived therefrom, thereby affecting the transparency of thepolymer product. Coloration is not desirable for many commercialapplications. U.S. Pat. No. 5,344,910 discloses that copolymers of para,para-PPPBP were found to have poor melt stability resulting in foamypolymer melts and moldings, and discoloration of the resin during meltprocessing.

It would therefore be desirable to develop a process for preparingrelatively pure phenolphthalein derivatives such as2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which can then beused for producing polycarbonates and other polymers having improvedproperties, such as lower color, e.g., a low yellowness index (YI) ofless than about 10, and higher weight average molecular weight.

BRIEF SUMMARY

Briefly, in one aspect, a method for producing a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises forming areaction mixture comprising at least one substituted or unsubstitutedphenolphthalein, at least one substituted or unsubstituted primaryhydrocarbyl amine, and an acid catalyst; and heating the reactionmixture to a temperature of less than 180° C. to remove a distillatecomprising water and form a crude2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product; where the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen.

In a second aspect, a method for purifying a crude2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises dissolvingthe crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product inan aqueous base to provide a first solution; treating the first solutionwith an activated carbon and filtering to provide a second solution; andtreating the second solution with an aqueous acid to precipitate apurified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of formula:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen, and further where saidpurified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprisesless than or equal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of the purified2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.

In a third aspect, a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidinecomprises less than or equal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine has aformula of:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen.

In a fourth aspect, a 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidinecomprises less than or equal to 1,000 parts per million of2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine, relativeto an overall weight of the 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.

In a fifth aspect, a method for producing a homopolycarbonate or acopolycarbonate comprising structural units derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, where the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than orequal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine impurityrelative to an overall weight of the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; is selected from thegroup consisting of a melt transesterification polymerization method andan interfacial polymerization method.

In a sixth aspect, a melt transesterification polymerization methodcomprises: combining a catalyst and a reactant composition to form areaction mixture, where the reactant composition comprises a carbonicacid diester, a 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, and atleast one aromatic dihydroxy compound comonomer, where the carbonic aciddiester is of the formula (ZO)₂C═O, wherein each Z is independently anunsubstituted or substituted alkyl radical, or an unsubstituted orsubstituted aryl radical, and, wherein the2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprises less than orequal to 1,000 parts per million of2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine relative toan overall weight of the 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine;and mixing the reaction mixture under reactive conditions for a timeperiod to produce a polycarbonate product.

In a seventh aspect, a polycarbonate comprises structural units derivedfrom a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen, and further where in the2-hydrocarbyl-3 ,3-bis(4-hydroxyaryl)phthalimidine comprises less thanor equal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.

In an eighth aspect, a lens comprises a polycarbonate, where thepolycarbonate comprises: structural units of formula derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen; and further where the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than orequal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of said2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; and a yellownessindex of less than 10 as measured on a 3 millimeter thick plaque inaccordance with ASTM D1925.

In a ninth aspect, a polycarbonate copolymer comprises structural unitsof formula derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

where R¹ is selected from the group consisting of a a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen; and further where the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than orequal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of said2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; where saidpolycarbonate copolymer has a yellowness index of less than 10 asmeasured on a 3 millimeter thick plaque in accordance with ASTM D1925.

In a tenth aspect, a polycarbonate copolymer comprises structural unitsof formula derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

where R¹ is selected from the group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen; where the polycarbonatecopolymer has a yellowness index of less than 10 as measured on a 3millimeter thick plaque in accordance with ASTM D1925.

The above described and other features are exemplified by the followingdetailed description.

DETAILED DESCRIPTION

For the purposes of this disclosure, the term “hydrocarbyl” is definedherein as a monovalent moiety formed by removing a hydrogen atom from ahydrocarbon. Representative hydrocarbyls are alkyl groups having 1 to 25carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl,heptyl, octyl, nonyl, undecyl, decyl, dodecyl, octadecyl, nonadecyl,eicosyl, heneicosyl, docosyl, tricosyl, and the isomeric forms thereof;aryl groups having 6 to 25 carbon atoms, such as ring-substituted andring-unsubstituted forms of phenyl, tolyl, xylyl, naphthyl, biphenyl,tetraphenyl, and the like; aralkyl groups having 7 to 25 carbon atoms,such as ring-substituted and ring-unsubtituted forms of benzyl,phenethyl, phenpropyl, phenbutyl, naphthoctyl, and the like; andcycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, and the like. The term “aryl” asused herein refers to various forms of aryl groups that have beendescribed hereinabove for the “hydrocarbyl” group.

The present disclosure is generally directed to producing and purifyingphenophthalein derivatives, which are suitable for use as monomers forpreparing polymers. An exemplary phenophthalein derivative,2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines is of formula (I):

wherein R¹ is selected from a group consisting of a hydrogen and ahydrocarbyl group, and R² is selected from the group consisting of ahydrogen, a hydrocarbyl group, and a halogen. For example, a2-aryl-3,3-bis(4-hydroxyaryl)phthalimidines can be prepared by thereaction of an aromatic amine (also referred to herein as “aryl amine”),e.g., an aniline, of formula (II):

wherein R¹ is as defined above; with a phenolphthalein of formula (III):

wherein R² is as previously defined. An acid catalyst is generally usedto facilitate formation of the phthalimidine product. Suitable acidcatalysts that can be used include amine salts of mineral acids.Examples of suitable mineral acids include hydrochloric acid, sulfuricacid, and nitric acid. Examples of suitable amines include primary,secondary, and tertiary amines having any combination of aliphatic andaromatic groups bonded to the amine nitrogen. Suitable examples of aminesalt catalysts include primary, secondary, and tertiary aminehydrochlorides. Hydrochloride salts of the primary aromatic amines offormula (II) are preferred since the amines of formula (II) also serveas the starting material for preparing the phthalimidines of formula(I). In one embodiment, the catalyst is introduced as a pre-formed saltinto the reactor. In another embodiment, the catalyst is generated inthe reactor by first charging the amine of formula (II) into thereactor, and then adding about ⅓ to about 1 part by weight of anappropriate mineral acid to phenolphthalein. In still anotherembodiment, about 0.1 parts to about 0.3 parts by weight of hydrogenchloride gas is introduced into a reactor charged with the aryl amine toform an appropriate amount of the aryl amine hydrochloride catalyst.More hydrochloric acid or more hydrogen chloride gas can also used, butis generally not required. A solvent can optionally be employed to formthe aryl amine hydrochloride. The solvent can then be removed (ifnecessary), and the aryl amine of formula (II) can be added, followed byaddition of phenolphthalein (III). The reaction of phenolphthalein (III)with the aryl amine (II) proceeds by a condensation reaction to form thedesired phthalimidine product (I). An excess of the aryl amine over thephenolphthalein may be used to keep the reaction proceeding in theforward direction. Likewise, a higher reaction temperature with orwithout removal of water by-product also facilitates product formation.However, in order to enhance the selectivity of2-hydrocarbyl-3,3-bis(4-hydroxyaryl) phthalimidine (I), and suppress theformation of undesired (2-hydroxyaryl)(4-hydroxyaryl)phthalimidineby-product, for example, it is preferred to control the temperature ofthe reaction mixture, and the rate of removal of water as well. Thetemperature of the reaction mixture and rate of water removal iscontrolled such that the crude PPPBP product is at least 97.5 areapercent pure 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in oneembodiment, and at least 98 area percent pure in another embodiment. Thechemical structure of (2-hydroxyaryl)(4-hydroxyaryl)phthalimidineby-product is shown in formula (IV) below.

wherein R¹ and R² are as previously described.

In one embodiment, the reaction temperature is controlled such that thewater by-product (calculated based on the moles of the phenolphthalein(III) which is preferably the limiting reagent) distills over a periodof about 12 hours to about 20 hours. If the reaction mixture is heatedsuch that the amount of water by-product distills within about 6 hours,the phthalimidine product of formula (I) has a relatively greater amountof the (2-hydroxyaryl)(4-hydroxyaryl)phthalimidine impurity shown informula (IV). Therefore, although a higher reaction temperature ensuresa quicker consumption of the phenolphthalein (III), it also leads toformation of a higher amount of the impurity of formula (IV). If thereaction temperature is not sufficiently high, and water by-product isnot removed, a relatively large amount of the phenolphthalein remainsunreacted, thereby leading to an inferior product, e.g., forms coloredbyproducts during melt mixing, forms low molecular weight polymers, andthe like. Thus, in one embodiment, the reaction mixture is heated to atemperature of about 150° C. to about 175° C. to remove water by-productand form the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product.In another embodiment, the reaction mixture is heated to a temperatureof about 150° C. to about 170° C.

By way of example, phenolphthalein (R² is H, R³ is phenyl in formula(III) was reacted with aniline (R³ is H in formula (II)) in the presenceof aniline hydrochloride as the catalyst to form2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (i.e., para,para-PPPBP),as shown in formula (V).

As will be discussed in the Example Section, the so-formed para,para-PPPBP was produced at high yields and was used to producepolycarbonates with a YI of less than about 10 and high weight averagemolecular weights. Moreover, the reaction did not produce any detectable(and undesirable) isomers of para, para-PPPBP such as the ortho,para-PPPBP isomer shown in Formula (VI) below.

Isolation of the desired phenolphthalein derivative from the reactionmixture includes quenching the mixture with an aqueous mineral acid,such as aqueous hydrochloric acid, and precipitating the crude2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The crude product isthen dissolved in an aqueous inorganic base comprising an alkali metalor alkaline earth metal hydroxide, carbonate, or bicarbonate to providea first solution. Aqueous sodium hydroxide is preferably used. Next, thefirst solution of the crude product is treated with a suitable solidadsorbent that can remove color-forming species present in the solution.In an embodiment, commercially available activated carbon can be used.Treatment with the activated carbon removes color-forming speciespresent in the solution. Suitable activated carbon include, but are notintended to be limited to, the NORIT series of activated carbonavailable from Norit Corporation, and those activated carbonscommercially available from E. Merck Company. The decolorizingefficiency of the activated carbon is indicated by its methylene bluenumber. Generally, an activated carbon with a relatively highermethylene blue number is less expensive than an activated carbon havinga relatively lower methylene blue number. Applicants find that evenactivated carbons having relatively higher methylene blue numbers areeffective decolorizing agents. After treatment with the activatedcarbon, the resulting mixture is filtered to provide a second solution.

In addition to functioning as a decolorizing agent, the activated carbontreatment also aids in selectively adsorbing the2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine isomericimpurity. Thus, one method for purifying a crude2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product comprisescontacting an aqueous base solution of the crude product with theactivated carbon and filtering off the carbon to provide a secondsolution. The second solution may again be treated in the same manner,if desired, to provide further reductions in the levels of the2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine impurity.In an embodiment, the step of treating and filtering the first solutionis done such that it is effective to reduce an amount of2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine to lessthan or equal to 1,000 parts per million relative to an overall weightof the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.

The decolorized and purified solution is next treated with an aqueousmineral acid, such as aqueous hydrochloric acid to precipitate2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The precipitate isthen finally stirred with an aliphatic alcohol to remove any trace ofthe phenolphthalein that may still be present and subsequently filteredto furnish purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.Suitable aliphatic alcohols include any aliphatic monohydric or dihydricalcohol. Non-limiting examples of suitable aliphatic alcohols includemethanol, ethanol, iso-propanol, iso-butanol, n-butanol, tertiarybutanol, n-pentanol, iso-pentanol, cyclohexanol, ethylene glycol,propylene glycol, neopentyl glycol and the like. In a particularembodiment, aliphatic monohydric alcohols that are miscible with water,such as methanol, ethanol, and isopropanol are used. Methanol is thepreferred aliphatic alcohol for removing phenolphthalein. Theso-produced and purified2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine preferably comprisesless than or equal to 1,000 parts per million of the2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine isomericimpurity. Further, the purified2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine preferably comprisesless than or equal to 1,000 parts per million of the phenolphthaleinstarting material.

In another embodiment, a method for purifying crude2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product comprisesdissolving the crude product in an aqueous base solution, treating theaqueous base solution of the crude product with the activated carbon,filtering off the carbon to provide a second solution, and acidifyingthe second solution with an aqueous acid to precipitate the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which has arelatively low level of the2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine impurity,e.g., less than 1,000 parts per million. The resulting product can thenbe contacted with an aliphatic alcohol in the manner previouslydescribed.

The general methods described hereinabove can advantageously be appliedfor preparing para, para-PPPBP having an undetectable level of ortho,para-PPPBP (as measured by HPLC technique). In one embodiment, thepurified para,para-PPPBP may also comprise up to 1,000 parts per millionof phenolphthalein.

The 2-hydrocarbyl-3,3-bis(4-hydroxyaryl) phthalimidines, including theexemplary 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, arecommercially valuable monomers or comonomers for producing a variety ofpolymers and polymer compositions formed by reactions of the phenolic OHgroups of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines.Suitable polymers that can be produced are polymers selected from thegroup consisting of homopolymers and copolymers of a polycarbonate, apolyestercarbonate, a polyester, a polyesteramide, a polyimide, apolyetherimide, a polyamideimide, a polyether, a polyethersulfone, apolycarbonate-polyorganosiloxane block copolymer, a copolymer comprisingaromatic ester, estercarbonate, and carbonate repeat units; and apolyetherketone. A suitable example of a copolymer comprising aromaticester, estercarbonate, and carbonate repeat units is the copolymerproduced by the reaction of a hydroxy-terminated polyester, such as theproduct of reaction of isophthaloyl chloride, and terephthaloyl chloridewith resorcinol, with phosgene and an aromatic dihydroxy compound, suchas bisphenol A.

In one embodiment, polycarbonates having desirable properties aresynthesized, wherein the polycarbonates include structural units offormula (VII):

which are derived from2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; wherein R¹ and R² areas described previously; and the C═O structural units are derived from aC═O donor such as phosgene or a carbonic acid diester; where the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than orequal to 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of said2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.

The polycarbonate composition may further comprise structural unitsderived from at least one other aromatic dihydroxy compound such as isrepresented by the general formula (VIII):

wherein each G¹ is an independently aromatic group; E is selected fromthe group consisting of an alkylene group, an alkylidene group, acycloaliphatic group, a sulfur-containing linkage group, aphosphorus-containing linkage group, an ether linkage group, a carbonylgroup, a tertiary nitrogen group, and a silicon-containing linkagegroup; R³ is a hydrogen or a monovalent hydrocarbon group each; Y¹ isindependently selected from the groups consisting of a monovalenthydrocarbyl group, an alkenyl group, an allyl group, a halogen, an oxygroup and a nitro group; each m is independently a whole number fromzero through the number of positions on each respective G¹ available forsubstitution; p is a whole number from zero through the number ofpositions on E available for substitution; t is a natural number greaterthan or equal to one; s is either zero or one; and u is a whole number.

Suitable examples of E include cyclopentylidene, cyclohexylidene,3,3,5-trimethylcyclohexylidene, methylcyclohexylidene,2-[2.2.1]-bicycloheptylidene, neopentylidene, cyclopentadecylidene,cyclododecylidene, and adamantylidene; a sulfur-containing linkage suchas sulfide, sulfoxide or sulfone, a phosphorus-containing linkage suchas phosphinyl, phosphonyl, an ether linkage, a carbonyl group, atertiary nitrogen group, and a silicon-containing linkage such as asilane or siloxy linkage.

In the aromatic dihydroxy comonomer compound shown in Formula (VIII),when more than one Y¹ substituent is present, they may be the same ordifferent. The same holds true for the R³ substituent. Where “s” is zeroin formula (VIII) and “u” is not zero, the aromatic rings are directlyjoined with no intervening alkylidene or other bridge. The positions ofthe hydroxyl groups and Y¹ on the aromatic nuclear residues G¹ can bevaried in the ortho, meta, or para positions and the groupings can be invicinal, asymmetrical or symmetrical relationship, where two or morering carbon atoms of the hydrocarbon residue are substituted with Y¹ andhydroxyl groups. In some embodiments, the parameters “t”, “s”, and “u”are each one; both G¹ radicals are unsubstituted phenylene radicals; andE is an alkylidene group such as isopropylidene. In particularembodiments, both G¹ radicals are p-phenylene, although both may beortho- or meta-phenylene or one ortho- or meta-phenylene and the otherpara-phenylene.

Some illustrative, non-limiting examples of aromatic dihydroxy compoundsof formula (VIII) include the dihydroxy-substituted aromatichydrocarbons disclosed by name or formula (generic or specific) in U.S.Pat. No. 4,217,438. Some particular examples of aromatic dihydroxycompound comonomers include, but are not intended to be limited to,2,4′-dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane,bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane,bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane,1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-2-chlorophenyl)ethane,2,2-bis(4-hydroxyphenyl)propane (bisphenol A);2,2-bis(3-chloro-4-hydroxyphenyl)propane;2,2-bis(3-bromo-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-3-methylphenyl)propane;2,2-bis(4-hydroxy-3-isopropylphenyl)propane;2,2-bis(3-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3-phenyl-4-hydroxyphenyl)propane;2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane;2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane;2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(3-chloro-4-hydroxy-5-methylphenyl)propane;2,2-bis(3-bromo-4-hydroxy-5-methylphenyl)propane;2,2-bis(3-chloro-4-hydroxy-5-isopropylphenyl)propane;2,2-bis(3-bromo-4-hydroxy-5-isopropylphenyl)propane;2,2-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)propane;2,2-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3-chloro-5-phenyl-4-hydroxyphenyl)propane;2,2-bis(3-bromo-5-phenyl-4-hydroxyphenyl)propane;2,2-bis(3,5-disopropyl-4-hydroxyphenyl)propane;2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane;2,2-bis(3,5-diphenyl-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)propane;2,2-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)propane;2,2-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)propane;2,2-bis(4-hydroxy-3-ethylphenyl)propane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,2,2-bis(3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane,bis(4-hydroxyphenyl)cyclohexylmethane,2,2-bis(4-hydroxyphenyl)-1-phenylpropane,1,1-bis(4-hydroxyphenyl)cyclohexane;1,1-bis(3-chloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane;1,1-bis(4-hydroxy-3-isopropylphenyl)cyclohexane;1,1-bis(3-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-dichloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-dibromo-4-hydroxyphenyl)cyclohexane;1,1-bis(4′-hydroxy-3′methylphenyl) cyclohexane (DMBPC),1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane; 4,4′-[1-methyl-4-(1-methyl-ethyl)- 1,3-cyclohexandiyl]bisphenol (1,3 BHPM),4-[1-[3-(4-hydroxyphenyl)-4-methylcyclohexyl]-1-methyl-ethyl]-phenol(2,8 BHPM), 3,8-dihydroxy-5a,10b-diphenylcoumarano-2′,3′,2,3-coumarane(DCBP), 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine,1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)cyclohexane;1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)cyclohexane;1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)cyclohexane;1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-chloro-5-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-disopropyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)cyclohexane;1,1-bis(3,5-diphenyl-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)cyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)cyclohexane;1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)cyclohexane;1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-3-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-3-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-dichloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-dibromo-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxy-5-methylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-chloro-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-4-hydroxy-5-isopropylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-t-butyl-5-chloro-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-5-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;bis(3-chloro-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3-bromo-5-phenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-disopropyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-di-t-butyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(3,5-diphenyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrachlorophenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetrabromophenyl)-3,3,5-trimethylcyclohexane;1,1-bis(4-hydroxy-2,3,5,6-tetramethylphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(2,6-dichloro-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;1,1-bis(2,6-dibromo-3,5-dimethyl-4-hydroxyphenyl)-3,3,5-trimethylcyclohexane;4,4-bis(4-hydroxyphenyl)heptane, 4,4 ′dihydroxy- 1,1-biphenyl;4,4′-dihydroxy-3,3′-dimethyl- 1,1-biphenyl; 4,4′-dihydroxy-3,3′-dioctyl-1,1-biphenyl; 4,4′-(3,3,5-trimethylcyclohexylidene)diphenol,4,4′-bis(3,5-dimethyl)diphenol, 4,4′-dihydroxydiphenyleth4,4′-dihydroxydiphenylthioether;1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene;1,3-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene;1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene,1,4-bis(2-(4-hydroxy-3-methylphenyl)-2-propyl)benzene2,4′-dihydroxyphenyl sulfone, 4,4′-dihydroxydiphenylsulfone (BPS),bis(4-hydroxyphenyl)methane, 2,6-dihydroxy naphthalene; hydroquinone;resorcinol, C1-3 alkyl-substituted resorcinols, 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol, 1-(4-hydroxyphenyl)- 1,3 ,3-trimethylindan-5-ol,and 2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl- 1,1′-spirobi[1H-indene]6,6′-diol. The most typical aromatic dihydroxycompound is Bisphenol A (BPA).

In some embodiments, an isosorbide comonomer can be used with the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomer to producepolycarbonate copolymers. Isosorbide, sometimes also called1,4:3,6-dianhydo-D-glucitol, is a rigid, chemically, and thermallystable aliphatic diol that tends to produce copolymers having higherglass transition temperatures, as compared to comonomer compositionswhich do not include isosorbide.

The carbonic acid diester described above has the general formula (IX):(ZO)₂C═O  (IX),wherein each Z is independently an unsubstituted or substituted alkylradical, or an unsubstituted or substituted aryl radical. Suitableexamples of carbonic acid diesters include, but are not intended to belimited to, ditolyl carbonate, m-cresyl carbonate, dinaphthyl carbonate,diphenyl carbonate, diethyl carbonate, dimethyl carbonate, dibutylcarbonate, dicyclohexyl carbonate, and combinations of two or morecarbonic acid diesters thereof. Diphenyl carbonate is widely used as acarbonic acid diester due to its low cost and ready availability on acommercial scale. If two or more of the carbonic acid diesters listedabove are utilized, preferably one of the carbonic acid diesters isdiphenyl carbonate.

Suitable carbonic acid diesters include the group of “activated aromaticcarbonates”. As used herein, the term “activated aromatic carbonate” isdefined as a diaryl carbonate that is more reactive than diphenylcarbonate in a transesterification reaction. Such activated aromaticcarbonates can also be represented by formula (IX), wherein each Z is anaryl radical having 6 to 30 carbon atoms. More specifically, theactivated carbonates have the general formula (X):

wherein Q and Q′ are each independently an ortho-positioned activatinggroup; A and A′ are each independently aromatic rings which can be thesame or different depending on the number and location of theirsubstituent groups, and a and a′ is zero to a whole number up to amaximum equivalent to the number of replaceable hydrogen groupssubstituted on the aromatic rings A and A′ respectively, provided a +a′is greater than or equal to 1. R and R′ are each independentlysubstituent groups such as alkyl, substituted alkyl, cycloalkyl, alkoxy,aryl, alkylaryl, cyano, nitro, or halogen. The term b is zero to a wholenumber up to a maximum equivalent to the number of replaceable hydrogenatoms on the aromatic ring A minus the number a, and the number b′ iszero to a whole number up to a maximum equivalent to the number ofreplaceable hydrogen atoms on the aromatic ring A′ minus the number a′.The number, type and location of R or R′on the aromatic ring is notintended to be limited unless they deactivate the carbonate and lead toa carbonate that is less reactive than diphenyl carbonate.

Non-limiting examples of suitable ortho-positioned activating groups Qand Q′ include (alkoxycarbonyl)aryl groups, halogens, nitro groups,amide groups, sulfone groups, sulfoxide groups, or imine groups withstructures indicated below:

wherein X is halogen or NO₂; M and M′ independently comprises N-dialkyl,N-alkyl aryl, alkyl, or aryl; and R⁴ is alkyl or aryl.

Specific non-limiting examples of activated aromatic carbonates includebis(o-methoxycarbonylphenyl)carbonate, bis(o-chlorophenyl)carbonate,bis(o-nitrophenyl)carbonate, bis(o-acetylphenyl)carbonate,bis(o-phenylketonephenyl)carbonate, bis(o-formylphenyl)carbonate.Unsymmetrical combinations of these structures, wherein the substitutionnumber and type on A and A′ are different, are also contemplated. Apreferred structure for the activated aromatic carbonate is anester-substituted diaryl carbonate having the formula (XI):

wherein R⁵ is independently at each occurrence a C₁-C₂₀ alkyl radical,C₄-C₂₀ cycloalkyl radical, or C₄-C₂₀ aromatic radical; R⁶ isindependently at each occurrence a halogen atom, cyano group, nitrogroup, C₁-C₂₀ alkyl radical, C₄-C₂₀ cycloalkyl radical, C₄-C₂₀ aromaticradical, C₁-C₂₀ alkoxy radical, C₄-C₂₀ cycloalkoxy radical, C₄-C₂₀aryloxy radical, C₁-C₂₀ alkylthio radical, C₄-C₂₀ cycloalkylthioradical, C₄-C₂₀ arylthio radical, C₁-C₂₀ alkylsulfinyl radical, C₄-C₂₀cycloalkylsulfinyl radical, C₄-C₂₀ arylsulfinyl radical, C₁-C₂₀alkylsulfonyl radical, C₄-C₂₀ cycloalkylsulfonyl radical, C₄-C₂₀arylsulfonyl radical, C₁-C₂₀ alkoxycarbonyl radical, C₄-C₂₀cycloalkoxycarbonyl radical, C₄-C₂₀ aryloxycarbonyl radical, C₂-C₆₀alkylamino radical, C₆-C₆₀ cycloalkylamino radical, C₅-C₆₀ arylaminoradical, C₁-C₄₀ alkylaminocarbonyl radical, C₄-C₄₀cycloalkylaminocarbonyl radical, C₄-C₄₀ arylaminocarbonyl radical, orC₁-C₂₀ acylamino radical; and c is independently at each occurrence aninteger 0-4. At least one of the substituents CO₂R⁵ is preferablyattached in the ortho position of formula (XI).

Examples of preferred ester-substituted diaryl carbonates include, butare not limited to, bis(methylsalicyl)carbonate (CAS Registry No.82091-12-1) (also known as BMSC orbis(o-methoxycarbonylphenyl)carbonate), bis(ethyl salicyl)carbonate,bis(propyl salicyl) carbonate, bis(butylsalicyl) carbonate, bis(benzylsalicyl)carbonate, bis(methyl 4-chlorosalicyl)carbonate and the like.Preferably, BSMC is used in melt polycarbonate synthesis due to itslower molecular weight and higher vapor pressure.

Some non-limiting examples of non-activating groups which, when presentin an ortho position, would not be expected to result in activatedcarbonates are alkyl, cycolalkyl or cyano groups. Some specific andnon-limiting examples of non-activated carbonates includebis(o-methylphenyl)carbonate, bis(p-cumylphenyl)carbonate,bis(p-(1,1,3,3-tetramethyl)butylphenyl)carbonate andbis(o-cyanophenyl)carbonate. Unsymmetrical combinations of thesestructures are also expected to result in non-activated carbonates.

Unsymmetrical diaryl carbonates, wherein one aryl group is activated andone aryl is inactivated, are useful if the activating group renders thediaryl carbonate more reactive than diphenyl carbonate.

One method for determining whether a certain diaryl carbonate isactivated or is not activated is to carry out a model melttransesterification reaction between the particular diaryl carbonate anda phenol such as para - (1,1,3,3-tetramethyl)butyl phenol (and comparingthe relative reactivity against diphenyl carbonate). This phenol ispreferred because it possesses only one reactive site, possesses a lowvolatility, and possesses a similar reactivity to bisphenol-A. The modelmelt transesterification reaction is carried out at temperatures abovethe melting points of the particular diaryl carbonate and phenol in thepresence of a transesterification catalyst, which is usually an aqueoussolution of sodium hydroxide or sodium phenoxide. Preferredconcentrations of the transesterification catalyst are at about 0.001mole percent based on the number of moles of the phenol or diarylcarbonate. Although a preferred reaction temperature is 200° C., thechoice of reaction conditions as well as catalyst concentration can beadjusted depending on the reactivity and melting points of the reactantsto provide a convenient reaction rate. The reaction temperature ispreferably maintained below the degradation temperature of thereactants. Sealed tubes can be used if the reaction temperatures causethe reactants to volatilize and affect the reactant molar balance. Adetermination of an equilibrium concentration of the reactants isaccomplished through reaction sampling during the course of the reactionwith subsequent analysis of the reaction mixture using well-knowndetection methods such as HPLC (high pressure liquid chromatography).Particular care needs to be taken so that the reaction does not continueafter the sample has been removed from the reaction vessel. This isaccomplished by cooling down the sample in an ice bath and by employinga reaction quenching acid, such as acetic acid in the water phase of theHPLC solvent system. It may also be desirable to introduce the reactionquenching acid directly into the reaction sample in addition to coolingthe reaction mixture. A preferred concentration for the reactionquenching acid, e.g., acetic acid in the water phase of the HPLC solventsystem, is about 0.05 mole percent. The equilibrium constant is thendetermined from the concentration of the reactants and product afterequilibrium is reached. Equilibrium is assumed to have been reached whenthe concentration of components in the reaction mixture reach a point oflittle or no change on sampling of the reaction mixture. The equilibriumconstant can be determined from the concentration of the reactants andproducts by methods well known to those skilled in the art. A diarylcarbonate which possesses a relative equilibrium constant(K_(diarylcarbonate)/K_(diphenylcarbonate)) of greater than 1 isconsidered to possess a greater reactivity than diphenyl carbonate andis a suitable activated aromatic carbonate for use in the presentdisclosure, whereas a diaryl carbonate which possesses an equilibriumconstant of 1 or less is considered to possess the same or have lessreactivity than diphenyl carbonate and is considered not to beactivated. It is generally preferred to employ an activated aromaticcarbonate with very high reactivity compared to diphenyl carbonate whenconducting transesterification reactions. Preferred are activatedaromatic carbonates with an equilibrium constant greater than at least1,000 times that of diphenyl carbonate.

Polycarbonate compositions comprising the structural unit of formula(VII) and carbonate units derived from the activated carbonatepreferably comprise at least one end group derived from the activatedcarbonate. In one embodiment, the end groups which are indicative of theactivated aromatic carbonate has a structure of formula (XII):

wherein Q is an ortho-positioned activating group; A is an aromaticring, n is a whole number of 1 to the number of replaceable hydrogengroups substituted on the aromatic ring A; R is a substituent groupselected from the group consisting of alkyl, cycloalkyl, alkoxy, aryl,cyano, nitro, and halogen; and b is zero to a whole number to the numberof replaceable hydrogen groups on the aromatic ring minus n. Q ispreferably a radical independently selected from the group consisting of(alkoxycarbonyl)aryl groups, halogens, nitro groups, amide groups,sulfone groups, sulfoxide groups, or imine groups with structures

wherein X comprises halogen or NO₂, M and M′ independently comprisesN-alkyl, N-aryl, or N-alkyl aryl; R⁴ comprises alkyl or aryl when n is1; and n has a value of 0 or 1.

Polycarbonates prepared using ester-substituted diaryl carbonates, suchas for example BMSC, may further comprise very low levels of structuralfeatures, which arise from side reactions taking place during the meltpolymerization reaction between an ester-substituted diaryl carbonate ofstructure (XI) and dihydroxy aromatic compounds of structure (VIII). Onesuch structural feature has a structure of formula (XIII):

wherein R⁷ is a halogen atom, cyano group, nitro group, C₁-C₂₀ alkylradical, C₄-C₂₀ cycloalkyl radical, C₄-C₂₀ aromatic radical, C₁-C₂₀alkoxy radical, C₄-C₂₀ cycloalkoxy radical, C₄-C₂₀ aryloxy radical,C₁-C₂₀ alkylthio radical, C₄-C₂₀ cycloalkylthio radical, C₄-C₂₀ arylthioradical, C₁-C₂₀ alkylsulfinyl radical, C₄-C₂₀ cycloalkylsulfinylradical, C₄-C₂₀ arylsulfinyl radical, C₁-C₂₀ alkylsulfonyl radical,C₄-C₂₀ cycloalkylsulfonyl radical, C₄-C₂₀ arylsulfonyl radical, C₁-C₂₀alkoxycarbonyl radical, C₄-C₂₀ cycloalkoxycarbonyl radical, C₄-C₂₀aryloxycarbonyl radical, C₂-C₆₀ alkylamino radical, C₆-C₆₀cycloalkylamino radical, C₅-C₆₀ arylamino radical, C₁-C₄₀alkylaminocarbonyl radical, C₄-C₄₀ cycloalkylaminocarbonyl radical,C₄-C₄₀ arylaminocarbonyl radical, or C₁-C₂₀ acylamino radical; and c isa whole number of 1-4. Typically such kinks are present only to a minorextent (e.g., 0.2 to 1 mole percent).

Structure (XIII) is termed an internal ester-carbonate linkage or kink.Without wishing to be bound by any theory, it is thought that structure(XIII) may arise by reaction of an ester-substituted phenol by-product,for example methyl salicylate, at its ester carbonyl group with adihydroxy aromatic compound or a hydroxyl group of a growing polymerchain. Further reaction of the ester-substituted phenolic hydroxy groupleads to formation of a carbonate linkage. Thus, the ester-substitutedphenol by-product of reaction of an ester-substituted diaryl carbonatewith a dihydroxy aromatic compound may be incorporated into the mainchain of a linear polycarbonate, for example.

Another structural feature present in melt transesterificationpolymerization reactions between ester-substituted diaryl carbonates anddihydroxy aromatic compounds is the ester-linked terminal end grouphaving a free hydroxyl group and have the structure (XIV):

wherein R⁷ and c are as defined above. Without wishing to be bound byany theory, it is believed that structure (XIV) may arise in the samemanner as structure (XIII), but without further reaction of theester-substituted phenolic hydroxy group. In the structures providedherein, the wavy line represents the polycarbonate polymer chainstructure. End capping of the polymer chains made by this method may beonly partial. In typical embodiments of polycarbonates prepared by themethods described herein, the free hydroxyl group content is from 7percent to 50 percent. This number may be varied by changing reactionconditions or by adding additional end-capping agents. In oneembodiment, wherein the activated carbonate used is BMSC, there will bean ester linked end group of structure (XV):

which possesses a free hydroxyl group. Thus, for example, if theterminal group of structure (XV) is attached to a para, para-PPPBP unitin the polycarbonate chain then it is designated hereinafter as“p,p-PPPBP-salicyl-OH end”, and if the terminal group of structure (XV)is attached to a BPA unit in the polycarbonate chain, it is hereinafterdesignated as “BPA-salicyl-OH end”.

The polycarbonates comprise structural units indicative of the activatedcarbonate. These structural units may be end groups produced whenactivated carbonate fragments act as end capping agents or may be kinksintroduced into the copolymer by incorporation of activated carbonatefragments.

The polycarbonate made, using the activated aromatic carbonate asdescribed above, may also have end-groups having structure (XVI):

where R, b, A, Q, and n are defined in the preceding sections.

In one embodiment the terminal end group having structure (XVI) is amethyl salicyl group of structure (XVII):

It could also include other salicyl groups such as the ethylsalicyl,isopropylsalicyl, and butylsalicyl groups.

A number of polymerization methods can be used for producing a polymer,such as a homopolycarbonate or a copolycarbonate, comprising structuralunits derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine,wherein the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprisesless than or equal to about 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of the purified2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. Suitable methods forfabricating polycarbonates, for example, include a melttransesterification polymerization method, an interfacial polymerizationmethod, and a bischloroformate polymerization method.

As used herein, the term “structural units derived from” when used inthe context of describing the portions of the copolycarbonates derivedfrom the aliphatic diol and the aromatic dihydroxy compounds refers tothe fact that both such monomers lose their respective hydrogen atomsupon incorporation in the polymer.

As used herein the term “activated carbonate” refers to a diarylcarbonate which is typically more reactive (either kinetically orthermodynamically) toward aromatic dihydroxy compounds than diphenylcarbonate under identical conditions. Activated carbonates are typically(but not necessarily) substituted diaryl carbonates.

As used herein the term “structural units indicative of the activatedcarbonate” means either internal “kinks” in the copolycarbonate or endgroups caused by incorporation of a fragment of an activated carbonatesuch as bismethylsalicyl carbonate (sometimes hereinafter referred to as“BMSC”).

The melt transesterification polymerization method is generally carriedout by combining a catalyst and a reactant composition to form areaction mixture; and mixing the reaction mixture under reactiveconditions for a time period effective to produce a polycarbonateproduct, wherein the reactant composition generally comprises a carbonicacid diester of the formula (ZO)₂C═O, wherein each Z is independently anunsubstituted or a substituted alkyl radical, or an unsubstituted or asubstituted aryl radical and the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than orequal to about 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of said2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.

During the manufacture of the polycarbonates by the melttransesterification method using the activated or unactivated carbonicacid diester, the amount of the carbonic acid diester comprises about0.8 moles to about 1.30 moles, and more specifically about 0.9 moles toabout 1.2 moles, based on one mole of the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine or any combination ofthe 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine and at least onearomatic dihydroxy comonomer.

Suitable melt transesterification catalysts include alkali metalcompounds, alkaline earth metal compounds, tetraorganoammoniumcompounds, and tetraorganophosphonium compounds, combinations comprisingat least one of the foregoing catalysts.

Specific examples of alkali metal compounds or alkaline earth metalcompounds include organic acid salts, inorganic acid salts, oxides,hydroxides, hydrides, and alcoholates of alkali metals and alkalineearth metals. Preferably, the catalyst is an alkali metal compound ofthe formula M₁X₁, wherein M₁ is selected from the group consisting oflithium, sodium, and potassium; and X₁ is selected from the groupconsisting of hydroxide and OAr, wherein Ar is a monovalent aromaticradical.

More specifically, examples of suitable alkali metal compounds include,but are not limited to, sodium hydroxide, potassium hydroxide, lithiumhydroxide, calcium hydroxide, magnesium hydroxide, sodium bicarbonate,potassium bicarbonate, lithium bicarbonate, sodium carbonate, potassiumcarbonate, lithium carbonate, sodium acetate, potassium acetate, lithiumacetate, lithium stearate, sodium stearate, potassium stearate, lithiumhydroxyborate, sodium hydroxyborate, sodium phenoxyborate, sodiumbenzoate, potassium benzoate, lithium benzoate, disodium hydrogenphosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate,disodium salts, dipotassium salts, and dilithium salts of bisphenol A,and sodium salts, potassium salts, lithium salts of phenol, and thelike.

Specific examples of alkaline earth metal compounds include, but are notlimited to, calcium hydroxide, barium hydroxide, magnesium hydroxide,strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesiumbicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate,magnesium carbonate, strontium carbonate, calcium acetate, bariumacetate, magnesium acetate, strontium acetate, strontium stearate, andthe like.

Exemplary tetraorganoammonium compounds include compounds comprisingstructure (XVIII):

wherein R⁸-R¹¹ are independently a C₁-C₂₀ alkyl radical, C₄-C₂₀cycloalkyl radical or a C₄-C₂₀ aryl radical and X³¹ is an organic orinorganic anion. Suitable anions (X³¹ ) include hydroxide, halide,carboxylate, sulfonate, sulfate, carbonate and bicarbonate. In oneembodiment, the transesterification catalyst comprises tetramethylammonium hydroxide.

In still other embodiments, the catalyst is a tetraorganophosphoniumcompound. Exemplary quaternary phosphonium compounds include compoundscomprising structure (XIX):

wherein R⁸-R¹¹ and X³¹ are as previously described. Illustrative anionsinclude hydroxide, halide, carboxylate, sulfonate, sulfate, carbonate,and bicarbonate.

Where X³¹ is a polyvalent anion such as carbonate or sulfate it isunderstood that the positive and negative charges in structures (XVIII)and (XIX) are properly balanced. For example, when R⁹-R¹² in structure(XVIII) are each methyl groups and X³¹ is carbonate, it is understoodthat X³¹ represents ½ (CO₃−⁻²) as will be appreciated by those skilledin the art.

Specific examples of tetraorganoammonium compounds andtetraorganophosphonium compounds include, but are not limited totetramethylammonium hydroxide, tetrabutylammonium hydroxide,tetraethylphosphonium hydroxide, tetrabutylphosphonium acetate,tetrabutylphosphonium hydroxide, and the like.

In one embodiment, the catalyst comprises tetrabutyl phosphoniumacetate. In an alternate embodiment, the catalyst comprises a mixture ofan alkali metal salt or alkaline earth metal salt with at least onequaternary ammonium compound, at least one quaternary phosphoniumcompound, or a mixture thereof. For example, the catalyst may be amixture of sodium hydroxide and tetrabutyl phosphonium acetate. Inanother embodiment, the catalyst is a mixture of sodium hydroxide andtetramethyl ammonium hydroxide.

In another embodiment, the catalyst comprises an alkaline earth metalsalt of an organic acid, an alkali metal salt of an organic acid, or asalt of an organic acid comprising both alkaline earth metal ions andalkali metal ions. Alkali metal and alkaline earth metal salts oforganic acids, such as for example, formic acid, acetic acid, stearicacid and ethylenediamine tetraacetic acid can also be used. In oneembodiment, the catalyst comprises magnesium disodium ethylenediaminetetraacetate (EDTA magnesium disodium salt).

In yet another embodiment, the catalyst comprises the salt of anon-volatile inorganic acid. By “non-volatile” it is meant that thereferenced compounds have no appreciable vapor pressure at ambienttemperature and pressure. In particular, these compounds are notvolatile at temperatures at which melt polymerizations of polycarbonateare typically conducted. The salts of non-volatile acids are alkalimetal salts of phosphites; alkaline earth metal salts of phosphites;alkali metal salts of phosphates; and alkaline earth metal salts ofphosphates. Suitable salts of non-volatile acids include NaH₂PO₃,NaH₂PO₄, Na₂H₂PO₃, KH₂PO₄, CsH₂PO₄, Cs₂H₂PO₄, or a mixture thereof Inone embodiment, the transesterification catalyst comprises both the saltof a non-volatile acid and a basic co-catalyst such as an alkali metalhydroxide. This concept is exemplified by the use of a combination ofNaH₂PO₄ and sodium hydroxide as the transesterification catalyst.

Any of the catalysts disclosed above may be used as combinations of twoor more substances. The catalyst may be added in a variety of forms. Thecatalyst may be added as a solid, for example as a powder, or it may bedissolved in a solvent, for example, in water or alcohol. The totalcatalyst composition is preferably about 1×10⁻⁷ to about 2×10⁻³ moles,and with about 1×10⁻⁶ to about 4×10⁻⁴ moles more preferred for each moleof the combination of the purified para, para-PPPBP and the aromaticdihydroxy compound comonomer.

Any of the catalysts described above for use in polycarbonate melttransesterification reactions may be used in reactions involvingactivated carbonates. It is often advantageous to use a combination ofsome amount of a salt of an alkaline earth metal and/or an alkali metal(i.e., an “alpha” catalyst) that does not degrade at temperatures usedthroughout the reaction together with a quaternary ammonium and/or aquaternary phosphonium compound that does degrade at a temperature usedin the reaction (i.e., a “beta” catalyst). The total amount of catalystemployed is about 1×10⁻⁷ to about 1×10⁻², and preferably about 1×10⁻⁷ toabout 2×10⁻³ moles cat per total moles of the mixture of para,para-PPPBP and aromatic dihydroxy compound employed.

The reactants for the polymerization reaction using an activatedaromatic carbonate can be charged into a reactor either in the solidform or in the molten form. Initial charging of reactants into a reactorand subsequent mixing of these materials under reactive conditions forpolymerization may be conducted in an inert gas atmosphere such as anitrogen atmosphere. The charging of one or more reactant may also bedone at a later stage of the polymerization reaction. Mixing of thereaction mixture is accomplished by any methods known in the art, suchas by stirring. Reactive conditions include time, temperature, pressureand other factors that affect polymerization of the reactants.Typically, the activated aromatic carbonate is added at a mole ratio ofabout 0.8 to about 1.23, and more 0.9 to about 1.2 and all sub-rangesthere between, relative to the total moles of aromatic dihydroxycompound and aliphatic diol.

The melt polymerization reaction using the activated aromatic carbonateis conducted by subjecting the above reaction mixture to a series oftemperature-pressure-time protocols. In some embodiments, this involvesgradually raising the reaction temperature in stages while graduallylowering the pressure in stages. In one embodiment, the pressure isreduced from about atmospheric pressure at the start of the reaction toabout 0.01 millibar (1 Pascal) or in another embodiment to 0.05 millibar(5 Pascals) in several steps as the reaction approaches completion. Thetemperature may be varied in a stepwise fashion beginning at atemperature of about the melting temperature of the reaction mixture andsubsequently increased to about 320° C. In one embodiment, the reactionmixture is heated from about ambient (about 21-23° C.) temperature toabout 150° C. The polymerization reaction starts at a temperature ofabout 150° C. to about 220° C., then is increased to about 220° C. toabout 250° C. and is then further increased to a temperature of about250° C. to about 320° C. and all sub-ranges there-between. The totalreaction time is about 30 minutes to about 200 minutes and allsub-ranges there between. This procedure will generally ensure that thereactants react to give polycarbonates with the desired molecularweight, glass transition temperature and physical properties. Thereaction proceeds to build the polycarbonate chain with production of aby-product such as, for example an ester-substituted alcohol e.g.,methyl salicylate. Efficient removal of the by-product may be achievedby different techniques such as reducing the pressure. Generally thepressure starts relatively high in the beginning of the reaction, suchas atmospheric pressure in one embodiment, and is lowered progressivelythroughout the reaction and temperature is raised throughout thereaction. Experimentation is needed to find the most efficientconditions for particular production equipment.

The progress of the reaction may be monitored by measuring the meltviscosity or the weight average molecular weight of the reaction mixtureusing techniques known in the art such as gel permeation chromatography.These properties may be measured by taking discreet samples or may bemeasured on-line. After the desired melt viscosity and/or molecularweight is reached, the final polycarbonate product may be isolated fromthe reactor in a solid or molten form. It will be appreciated by aperson skilled in the art, that the method of making polycarbonates asdescribed in the preceding sections may be made in a batch or acontinuous process and the process disclosed herein is essentiallypreferably carried out in a solvent free mode. Reactors chosen shouldideally be self-cleaning and should minimize any “hot spots.”

In one embodiment, the aliphatic homopolycarbonate andaliphatic-aromatic copolycarbonate may be prepared in an extruder inpresence of one or more catalysts, wherein the carbonating agent is anactivated aromatic carbonate. The reactants for the polymerizationreaction can be fed to the extruder in powder or molten form. In oneembodiment, the reactants are dry blended prior to addition to theextruder. The extruder may be equipped with pressure reducing devices(e.g., vents), which serve to remove the activated phenol by-product andthus drive the polymerization reaction toward completion. The molecularweight of the polycarbonate product may be manipulated by controlling,among other factors, the feed rate of the reactants, the type ofextruder, the extruder screw design and configuration, the residencetime in the extruder, the reaction temperature and the pressure reducingtechniques present on the extruder. The molecular weight of thepolycarbonate product may also depend upon the structures of thereactants, such as, activated aromatic carbonate, aliphatic diol,dihydroxy aromatic compound, and the catalyst employed. Many differentscrew designs and extruder configurations are commercially availablethat use single screws, double screws, vents, back flight and forwardflight zones, seals, side-streams and sizes. One skilled in the art mayhave to experiment to find the best designs using generally knownprincipals of commercial extruder design. Vented extruders similar tothose that are commercially available may also be used.

The process disclosed herein can be used to prepare PPPBPhomopolycarbonate and copolycarbonates having a weight average molecularweight (Mw) of about 3,000 to about 150,000 and a glass transitiontemperature (Tg) of about 80° C. to about 300° C. The number averagemolecular weights (Mn) of the homopolycarbonate and copolycarbonates isfrom about 1,500 to about 75,000. The transparency of cast films madefrom the polycarbonate or copolycarbonates prepared in accordance withthe present disclosure is greater than about 85 percent, as determinedby a Haze Guard Instrument.

In monitoring and evaluating polycarbonate synthesis, it is ofparticular interest to determine the concentration of Fries productpresent in the polycarbonate. The generation of significant Friesproduct can lead to polymer branching, resulting in uncontrollable meltbehavior. In the process of preparing polycarbonates described herein,some branching reaction (Fries reaction) takes place (especially athigher temperatures and exacerbated by alpha catalysts) resulting in aFries product. Fries products are defined as structural units of theproduct polycarbonate which upon hydrolysis of the product polycarbonateaffords a carboxy-substituted dihydroxy aromatic compound bearing acarboxy group adjacent to one or both of the hydroxy groups of thecarboxy-substituted dihydroxy aromatic compound. For example, inbisphenol A polycarbonate prepared by a melt polymerization method inwhich Fries reaction occurs, the Fries product comprises structure (XX)below, which affords 2-carboxy bisphenol A upon complete hydrolysis ofthe product polycarbonate. As indicated, the Fries product may serve asa site for polymer branching, the wavy lines of structure (XX)indicating a polymer chain structure.

The polycarbonates prepared using the activated carbonate by thedisclosed method have a concentration of Fries product of less thanabout 500 parts per million (ppm) as measured by high performance liquidchromatography (HPLC). The Fries concentration is much less than what isobtained in a conventional melt polymerization process that usesdiphenyl carbonate as the carbonic acid diester. Fries products aregenerally undesirable for certain polycarbonates because excessivelevels can adversely affect certain physical properties.

In the interfacial polymerization method,2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, with or without oneor more comonomers, and phosgene are reacted in the presence of an acidacceptor and an aqueous base to produce said polycarbonate. Tertiaryamines, such as for example, trialkylamines are preferably used as acidacceptors. An exemplary trialkylamine is triethylamine. Suitable aqueousbases include, for example, the alkali metal hydroxides, such as sodiumhydroxide. The interfacial method can be used for producingpolycarbonates comprising structural units derived from2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, and preferably havingmolecular weights greater than about 50,000, relative to polystyrenestandard.

The interfacial method described above can be suitably adapted toproduce polycarbonates through the intermediate formation of2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine bischloroformate. Thismethod is sometimes called the bischloroformate polymerization method.In one embodiment, the method comprises reacting a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine with phosgene in anorganic solvent, and then reacting the bischloroformate either with a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, or an aromaticdihydroxy compound in the presence of an acid acceptor and an aqueousbase to form the polycarbonate.

The interfacial polymerization method and the bischloroformatepolymerization method can be carried in a batch or a continuous modeusing one or more reactor systems. To carry out the process in acontinuous mode, one or more continuous reactors, such as for example, atubular reactor can be used. In one embodiment, the continuous methodcomprises introducing into a tubular reactor system phosgene, at leastone solvent (example, methylene chloride), at least one bisphenol,aqueous base, and optionally one or more catalysts (example, atrialkylamine) to form a flowing reaction mixture. The flowing mixtureis then passed through the tubular reactor system until substantiallyall of the phosgene has been consumed. The resulting mixture is nexttreated with a mixture comprising an aqueous base, at least oneend-capping agent, optionally one or more solvents, and at least onecatalyst. The end-capped polycarbonate thus formed is continuouslyremoved from the tubular reactor system. The process can be used forpreparing end-capped polycarbonate oligomers (generally polycarbonateshaving a weight average molecular weight of less than or equal to 10,000daltons) or polymers having a weight average molecular weight of greaterthan 10,000 daltons. The processes outlined hereinabove can also besuitably adapted, for example, to produce end-capped polycarbonates viathe intermediate formation of a mixture comprising a bisphenolmonochloroformate or a bisphenol bischloroformate.

In another embodiment, polymer blends comprise the polymers describedpreviously and at least one thermoplastic polymer. The at least onethermoplastic polymer is selected from the group consisting of vinylpolymers, acrylic polymers, polyacrylonitrile, polystyrenes,polyolefins, polyesters, polyurethanes, polyamides, polysulfones,polyimides, polyetherimides, polyphenylene ethers, polyphenylenesulfides, polyether ketones, polyether ether ketones, ABS resins,polyethersulfones, poly(alkenylaromatic) polymers, polybutadiene,polyacetals, polycarbonates, polyphenylene ethers, ethylene-vinylacetate copolymers, polyvinyl acetate, liquid crystal polymers,ethylene-tetrafluoroethylene copolymer, aromatic polyesters, polyvinylfluoride, polyvinylidene fluoride, polyvinylidene chloride,tetrafluoroethylene, polycarbonate-polyorganosiloxane block copolymers,copolymers comprising aromatic ester, estercarbonate, and carbonaterepeat units; mixtures, and blends comprising at least one of theforegoing polymers.

The polymers and polymer blends described hereinabove are valuable forproducing articles. In one embodiment, an article comprises a polymercomprising structural units derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which comprises lessthan or equal to about 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine, relativeto an overall weight of the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. In anotherembodiment, an article comprises a polymer comprising structural unitsderived from a 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, whichcomprises less than or equal to about 1,000 parts per million of2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine, relativeto an overall weight of said2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.

Polymers, particularly polycarbonate homopolymers and copolymerscomprising structural units derived from the high purity2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in general, andpara,para-PPPBP in particular have a yellowness index of less than 10 asmeasured on a 3 millimeter thick plaque in accordance with ASTM D1925 inone embodiment, less than 5 in another embodiment, and less than 2 instill another embodiment. Hence these polycarbonate polymers are usefulfor producing articles having a number of useful properties, such as alow residual color. The articles also exhibit excellent heat aging.Thus, extruded articles have low color values (as measured by yellownessindex, YI) even after heat aging, such as, for example, a YI of lessthan about 2 after heat aging in air at 155° C.-160° C. for about 500hours in one embodiment, and a YI of less than about 0.5 after heataging in air at 120° C. for about 500 hours in another embodiment. Thepolycarbonate homopolymers and copolymers have high glass transitiontemperatures of higher than or equal to about 180° C. One of the uniqueproperties of these polycarbonates, especially those that have glasstransition temperatures of greater than or equal to about 180° C. isthat during melt processing they exhibit a shear-thinning behavior. Thatis, the polymers have the ability to flow under an applied shear.Therefore, standard melt processing equipment used for BPApolycarbonates can advantageously be used for producing articles. Thepolycarbonates also have high transparency, as measured by percent lighttransmission, of greater than or equal to about 85 percent. Moreover,the copolycarbonate is especially useful for articles that arepreferably made form a polymer having transparency and the otheradvantageous properties of a BPOA homopolymer polycarbonate but with asignificantly higher Tg. Lenses in applications where they are exposedto heat are a good example of such an application.

The polycarbonate compositions disclosed herein are particularlyvaluable for producing a variety of lenses suitable for diverseapplications. In an embodiment, the lens comprises a polycarbonate,which comprises structural units of formula (VII) derived from a2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprising less thanor equal to about 1,000 parts per million of a2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relativeto an overall weight of said2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; and a yellownessindex of less than 10 as measured on a 3 millimeter thick plaque inaccordance with ASTM D1925 in one embodiment, and less than 2 in anotherembodiment. Non-limiting examples of suitable articles include anautomotive headlamp inner lens, an automotive headlamp outer lens, anautomotive fog lamp lens, an automotive bezel, a medical device, adisplay device, electrical connectors, under the hood automotive parts,and projector lens. Examples of suitable display devices include alaptop computer screen, a liquid crystal display screen, and an organiclight-emitting diode display screen.

The polycarbonates disclosed herein may also be combined with effectiveamounts of one or more of various types of additives used selected fromthe group consisting of fillers, fire retardants, drip retardants,antistatic agents, UV stabilizers, heat stabilizers, antioxidants,plasticizers, dyes, pigments, colorants, processing aids, and mixturesthereof. These additives are known in the art, as are their effectivelevels and methods of incorporation. Effective amounts of the additivesvary widely, but they are usually present in an amount up to about 50%or more by weight, based on the weight of the entire composition.Especially preferred additives include hindered phenols, thio compoundsand amides derived from various fatty acids. The preferred amounts ofthese additives generally ranges up to about 2% total combined weightbased on the total weight of the composition.

EXAMPLES

In the following examples, molecular weights were measured by gelpermeation chromatography using a polystyrene standard. Glass transitiontemperatures of the polycarbonates were measured by differentialscanning calorimetry by heating the sample at the rate of 10° C. to 20°C. per minute under nitrogen. Yellow index was measured using ASTM D1925test method on plaques of 3 millimeter thickness and on films of 0.2millimeter thickness. Films were prepared in a petri dish by castingfrom a solution of 1.1 grams of a polycarbonate in about 10 millilitersof chloroform.

HPLC analysis was generally carried out by using a solution of about 50milligrams of the sample dissolved in about 10 milliliters of methanol.The HPLC instrument was equipped with a C18 (reverse phase) columnmaintained at a temperature of 40° C., and an ultraviolet detectorcapable of detecting components at a wavelength of 230 nanometers. Asolvent mixture of methanol and water of varying relative proportionswas used. The flow rate was maintained at 1 milliliter per minute. Areapercent assay was computed from the area value for each peak detected inthe chromatogram divided by the total area from all peaks detected. Tomeasure weight percent assay, calibration curves for p,p-PPPBP,o,p-PPPBP, and phenolphthalein were first generated. Then the weightpercent of a given component in a sample was calculated using thesecalibration curves.

All melt transesterification polymerizations were carried out usingeither diphenyl carbonate or bismethylsalicyl carbonate. The catalystfor all of the polymerization runs was prepared by taking appropriatealiquots of a stock solution of aqueous sodium hydroxide and a 25 weightpercent aqueous tetramethylammonium hydroxide. Molded articles wereprepared by first preparing pellets of the molding compositions using a25 millimeter ZSK twin-screw extruder, followed by injection moldingusing a L&T DEMAG 60 molding machine having a clamping capacity of 60ton, a screw diameter of 25 millimeters, and shot capacity of 58 gramsof polystyrene.

Comparative Example 1

In this example, a prior art process was employed to isolate a para,para-PPPBP product.

The prior art process included refluxing a mixture of phenolphthalein(20 grams (g)), aniline hydrochloride (20 g), and 60 ml of aniline at atemperature from about 180° C. to about 185° C. for 5 hours undernitrogen. The dark solution was then stirred into a mixture of 100 gramsof ice and 70 grams of concentrated HCl. The violet crystalline productwas filtered off and washed with water. The crystals were then dissolvedin ice-cold 10% sodium hydroxide solution. The solution was treated with0.2 g active carbon, and then filtered. By drop-wise addition ofconcentrated HCl into the stirred batch, the color changed to a brightpink, then to a pure white, thick slurry with a pH of 3-4. Theprecipitated phenolphthalein anilide was then washed neutral with waterand dried under vacuum at 70° C. The crude crystals gave a melting pointof 288-291° C. with a yield of 79%. Double recrystallization fromethanol, followed by drying the crystals under vacuum at 150° C. gavethe product. The results are shown in Table 1.

Comparative Example 2

The procedure described in Comparative Example 1 was repeated exceptthat the water by-product was removed. The results are shown in Table 1.

Comparative Example 3. In this Example, phenolphthalein and aniline werereacted in the presence of hydrochloric acid. The reaction was carriedout without removing the water by-product.

Phenolphthalein (38.1 grams), aniline (65 milliliters), and concentratedhydrochloric acid (20.5 milliliters) were charged into a reaction vesseland heated such that the temperature of the reaction mixture was 155°C.-165° C. The temperature of the reaction was adjusted to 155-165 C.After being heated for about 14-15 hours, the reaction mixture waspoured into a mixture of hydrochloric acid and water. The solid product,which precipitated, was collected by filtration. Analysis of the solidproduct by HPLC indicated about 6 area percent of para,para-PPPBP andabout 93 area percent of phenolphthalein, wherein ortho, para-PPPBP wasnot detected (less than 10 parts per million, the detection limit of theHPLC method). The results are shown in Table 1.

Comparative Examples 4 and 5

Polymerization runs were carried out using the procedure described inExample 2 below with the para,para-PPPBP prepared in accordance withComparative Examples 1 and 2, respectively. The molecular weights of thepolycarbonate prepared by this method and the YI of films prepared bysolution casting of the polycarbonates are shown in Table 2.

Comparative Example 6

This Example describes the preparation of a polycarbonate copolymerusing the same method as disclosed in Example 4 below, with a para,para-PPPBP monomer prepared in accordance with Comparative Example 2.

Example 1

This Example describes the preparation of para,para-PPPBP containingless than or equal to about 1,000 parts per million of ortho, para-PPPBPisomer impurity.

Phenolphthalein (31. 8 grams), aniline (65 milliliters), andconcentrated hydrochloric acid (20.5 milliliters) were taken in areaction flask fitted with a Dean Stark condenser. The reaction mass washeated to an internal temperature of 155° C.-165° C. Water was collectedduring the course of the reaction. After being heated at thistemperature for 14-15 hours, the reaction mixture was poured into amixture of hydrochloric acid and water. The crude product, whichprecipitated, was collected by filtration and dissolved in an aqueoussodium hydroxide solution containing activated charcoal. After beingstirred for about 30 minutes, the mixture was then filtered to removethe charcoal. The charcoal treatment step was repeated once more, andthe resulting filtrate was treated with concentrated hydrochloric acidto precipitate para, para-PPPBP as a white solid, which was thenfiltered. The solid product was refluxed in methanol (approximately fourvolumes of methanol were taken relative to the volume of the solidproduct) for about an hour, cooled, and filtered to provide the finalproduct which was found by HPLC analysis to have a para, para-PPPBPpurity of 99.9 area percent. The yield of the isolated product was 80 to82 percent of theory. The results are shown in Table 1, where “ND”indicates, “not detected”.

Example 2

This Example describes the general melt transesterification method usedfor preparing polycarbonate copolymers using 47 weight percent ofdiphenyl carbonate and 53 weight percent of a monomer mixture consistingof 75 weight percent of BPA and 25 weight percent of the purifiedpara,para-PPPBP prepared in accordance with Example 1.

A glass polymerization reactor was passivated by soaking the reactor ina bath containing 1 molar aqueous hydrochloric acid solution. After 24hours, the reactor was thoroughly rinsed with demineralized water, andfinally, with deionized water to ensure that all traces of acid andother contaminants were removed. The reactor was then thoroughly driedand charged with the appropriate amounts of the purified para,para-PPPBPmonomer or a monomer mixture comprising the purified para,para-PPPBP anddiphenyl carbonate monomers. The reactor was then mounted in apolymerization assembly and checked to ensure that no leaks werepresent. The catalyst solutions (2.5×10⁻⁴ mol of aqueoustetramethylammonium hydroxide and 5×10⁻⁶ mole of aqueous sodiumhydroxide), as prepared above, were then introduced into the reactorusing a syringe. The atmosphere inside the reactor was then evacuatedusing a vacuum source and purged with nitrogen. This cycle was repeated3 times after which the contents of the reactor were heated to melt themonomer mixture. When the temperature of the mixture reached about 180°C. to about 190° C., the stirrer in the reactor was turned on andadjusted to about 40 to about 80 revolutions per minute (rpm) to ensurethat the entire solid mass fully melted, a process that usually tookabout 15 to about 20 minutes. Next, the reaction mixture was heated to atemperature of about 230° C., while the pressure inside the reactor wasadjusted to about 170 millibar using a vacuum source. Thistemperature-pressure-time regime was designated as P1. After stirringthe reaction mass at this condition for about 1 hour, the reactiontemperature was raised to about 270° C. while readjusting the pressureto around 20 millibar. After being maintained at this condition,designated as P2, for about 30 minutes, the temperature of the reactionmixture was raised to 300° C. while bringing the pressure down to lessthan or equal to about 1 millibar. After being maintained at thiscondition, designated as P3, for about 30 minutes, the temperature ofthe reaction mixture was raised to 300° C. while bringing the pressuredown to less than or equal to about 1 millibar. After being maintainedat this condition, designated as P4, for about 30 minutes, thetemperature of the reaction mixture was raised to about 315° C. whilebringing the pressure down to less than or equal to about 1 millibar.After allowing the reaction to proceed under these conditions,designated as P5, for about 10 minutes to about 20 minutes, the pressureinside the reactor was brought to atmospheric pressure and the reactorwas vented to relieve any excess pressure. Product isolation wasaccomplished by breaking the glass nipple at the bottom of the reactorand collecting the material. In the cases where the product was of avery high molecular weight, the hot molten polymer was dropped down bypressurizing the reactor with nitrogen gas.

Example 3. This Example describes the melt transesterification methodused for preparing polycarbonate copolymer using 55 weight percent ofbismethylsalicyl carbonate and 45 weight percent of a monomer mixturecomprising 75 weight percent of BPA and 25 weight percent of purifiedpara,para-PPPBP (prepared as described in Example 1). The polymerizationruns were carried using

The same procedure as described above was used to charge the necessaryreaction ingredients into the reactor. However, after the heating stepto fully melt the monomer, the reaction mixture was heated to atemperature of about 210° C. at atmospheric pressure (about 910millibar). After stirring the reaction mass at this condition for about10 minutes, the pressure was reduced to about 100 millibars, andmaintained at this condition for about 15 minutes. Next, the reactionmixture was heated to a temperature of about 310° C. while bring thepressure down to less than or equal to about 1 millibar. After beingstirred under these conditions for about 15 minutes, the pressure insidethe reactor was brought to atmospheric pressure and the reactor wasvented to relieve any excess pressure. Product isolation wasaccomplished using the same procedure as described in Example 2.

The procedure described hereinabove was used to prepare polycarbonatecopolymers having M_(w) from about 45,000 to about 75,000.

Example 4

This Example describes the general procedure for the interfacialpolymerization method using a monomer mixture comprising a 75:25 moleratio of purified para,para-PPPB.P (prepared in accordance with methoddescribed in Example 1) and BPA, respectively. The procedure used hereis as described in U.S. Pat. No. 5,804,525, where the monomer mixture(as described above) and para-cumylphenol was reacted with phosgene inmethylene chloride in the presence of tetrabutylammonium bromide. Duringaddition of phosgene, the pH of the reaction mixture was maintained atabout 10.5 by slow addition of aqueous sodium hydroxide. After phosgeneaddition, triethylamine was added to react out trace levels ofchloroformate derivatives present in the reaction mixture. Thepolycarbonate thus prepared had the following physical properties: YI(yellowness index, ASTM D1925): 9; Notched izod at ambient temperature(ASTM D256): 4.9 foot-pound per inch; Glass transition temperature: 191°C.; Delta YI (ASTM D1925) of molded article after heat aging in air inan oven maintained at 155° C. -160° C. for 500 hours: less than 2; DeltaYI (ASTM D1925) after heat aging in air in an oven maintained at 120° C.for 500 hours: less than 0.5. TABLE 1 HPLC analysis (Area percent)Example para, para-PPPBP Phenolphthalein ortho, para-PPPBP 1* 97.5 0.52   2* 98.5 0.11 1.35 3* 6.2 93.1 ND 1  99.9 0.05 ND*Indicates Comparative Example.

TABLE 2 para, para- Polymerization PPPBP M_(w) of poly- Run ExampleExample carbonate YI of polycarbonate Number Number (Daltons) (article)4* 1* 21,000   6.3 (film) 5* 2* 19,000   4.3 (film) 2  1  30,000   0.8(film) 3  1  63,000   0.6 (film) 4  1  62,000   <1 (film); 9 (moldedplaque) 6* 2* 44,000    59 (molded plaque)*Indicates Comparative Example.

Table 1 shows the effect of the purity of the2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines on the molecularweight and yellowness indices of films of the polymers derived usingthese phthalimidines as a comonomer with bisphenol A. ComparativeExamples 1 and 2 indicate that a higher level of the2-hydrocarbyl-3,3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine impurity(or sometimes herein generally referred to as “ortho, para-PPPBPimpurity”) in the para,para-PPPBP comonomer results in a lower molecularweight and a relatively higher film yellowness index for the polymer.Without wishing to be bound by theory, applicants believe that theortho, para impurity, being relatively more sterically hindered than thecorresponding para,para-phthalimidine isomer acts as a chain terminationagent, thereby limiting polymer chain length and molecular weight.However, Example 1 shows that when para,para-PPPBP with no detectable(by HPLC) level of the ortho, para-impurity is copolymerized with BPA,the polymer weight average molecular weight is substantially higher(31,000). Furthermore, the polymer film has a relatively much loweryellowness index of 0.8. Comparative Example 3 shows that even if thereaction temperature is maintained at about 155° C. to 165° C., if wateris not removed during the reaction to form para,para-PPPBP, the reactiongives a very poor yield (about 6 area percent) of para,para-PPPBP.

Moreover, when the compound (IV) was prepared in accordance with theprocedure of Comparative Example 1, wherein phenolphthalein and excessaniline are heated under reflux in a nitrogen atmosphere for about 5hours without removal of water, such that the reaction temperature isabout 180° C. to about 185° C., the para, para-PPPBP that was isolatedafter the double crystallization from ethanol contained about 2.5 areapercent of an undesired side-product that has been analyticallydetermined to be isomeric ortho, para-PPPBP.

On the other hand, if the reaction is carried out in the same manner asdescribed in Comparative Example 1, but the water by-product isdistilled out over the same period of about 5 hours, HPLC analysisindicated that the isolated product contains about 98.5 area percent ofpara,p ara-PPPBP, about 0.11 area percent of phenolphthalein, and about1.35 area percent of the impurity compound (IV). This indicates thatwater removal is necessary to lower the formation of compound (IV).However, when the reaction is conducted using a reaction temperature ofabout 160° C. to about 165° C., water removal takes about 14 hours, andthe impurity (IV) was undetectable in the isolated para, para-PPPBPproduct relative to the measurement sensitivity of the HPLC method(detection limit of 10 parts per million for compound (IV)).Furthermore, the product only contains about 0.05 area percent ofphenolphthalein. In contrast, when the reaction was conducted at areaction temperature of about 160° C. to about 165° C., but the waterwas not removed, HPLC analysis of the reaction mixture after 14 hours ofheating indicated formation of only about 6.2 area percent of para,para-PPPBP with the majority (about 92 area percent) of phenolphthaleinstarting material remaining unreacted. These results clearly indicatethat the preferred method for forming para, para-PPPBP in high isolatedyield and high isomeric purity is to maintain the reaction temperatureat about 160° C. to about 165° C. with water removal over a period ofabout 14 hours. Under such conditions, utilization of phenolphthaleinfor selectively forming para, para-PPPBP is enhanced, and formation ofthe ortho, para-PPPBP is minimized. These techniques can be suitablyadapted to prepare the other2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidines described previously.

The results shown in Table 1 (Example 1), and Table 2, (Examples 2 and4) clearly indicate that purified para,para-PPPBP is useful forpreparing polycarbonates of high molecular weight (e.g., M_(w) of62,000), which are valuable for producing films and molded articleshaving a yellowness index of less than 10. Moreover, the molded articlesshow excellent resistance to heat aging, as shown in Example 4, thusmaking such polycarbonates valuable for high heat applications.

While the disclosure has been described with reference to a preferredembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the disclosure. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the disclosure without departing fromessential scope thereof. Therefore, it is intended that the disclosurenot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the disclosurewill include all embodiments falling within the scope of the appendedclaims.

1. A method for producing a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, comprising: forming a reaction mixture comprising at least one substituted or unsubstituted phenolphthalein, at least one substituted or unsubstituted primary hydrocarbyl amine, and an acid catalyst; and heating the reaction mixture to a temperature of less than 180° C. to remove a distillate comprising water and form a crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product; wherein said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen.
 2. The method of claim 1, wherein said crude PPPBP product is at least 97.5 area percent pure 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 3. The method of claim 1, wherein said crude PPPBP product is at least 98 area percent pure 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 4. The method of claim 1, further comprising: dissolving said crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product in an aqueous base to provide a first solution; treating and filtering said first solution with a solid adsorbent to provide a second solution; and treating said second solution with an aqueous acid to precipitate said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 5. The method of claim 4, wherein said treating and filtering is done at least 2 times.
 6. The method of claim 4, wherein said aqueous base comprises an alkali metal or alkaline earth metal hydroxide, carbonate, or bicarbonate.
 7. The method of claim 4, wherein said adsorbent comprises an activated carbon.
 8. The method of claim 4, wherein said treating and filtering said first solution is effective to reduce an amount of 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine to less than or equal to 1,000 parts per million relative to an overall weight of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 9. The method of claim 1, further comprising contacting said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine with an aliphatic alcohol to produce a purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprising less than or equal to 1,000 parts per million of a substituted or an unsubstituted phenolphthalein relative to an overall weight of said purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 10. The method of claim 9, wherein said aliphatic alcohol comprises methanol, ethanol, iso-propanol, iso-butanol, n-butanol, tertiary butanol, n-pentanol, iso-pentanol, cyclohexanol, ethylene glycol, propylene glycol, neopentyl glycol or mixtures of the foregoing aliphatic alcohols.
 11. The method of claim 1, wherein said acid catalyst is selected from a group consisting of a substituted or an unsubstituted aliphatic amine hydrochloride, an aromatic amine hydrochloride, or mixtures of the foregoing amine hydrochlorides.
 12. The method of claim 1, wherein said heating the reaction mixture comprises heating to a temperature of about 150° C. to about 175° C.
 13. The method of claim 1, wherein said heating the reaction mixture comprises heating to a temperature of about 1 50° C. to about 170° C.
 14. The method of claim 1, wherein said heating the reaction mixture is for a time of about 12 hours to about 20 hours.
 15. A purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine prepared in accordance with the method of claim
 1. 16. The purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of claim 15, comprising less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine, relative to an overall weight of said purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 17. The method of claim 1, wherein said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine is 2-phenyl-3,3-bis(4-hydroxphenyl)phthalimidine.
 18. The method of claim 17, wherein said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprises less than or equal to 1,000 parts per million of a 2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine relative to an overall weight of said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
 19. A method for purifying a crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, comprising: dissolving the crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine product in an aqueous base to provide a first solution; treating said first solution with an activated carbon and filtering to provide a second solution; and treating said second solution with an aqueous acid to precipitate a purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of formula:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen, wherein said purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relative to an overall weight of said purified 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 20. The method of claim 19, wherein said treating said first solution with an activated carbon and filtering to provide a second solution is done at least 2 times.
 21. A 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprising less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein said 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine has a formula of:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen.
 22. The 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of claim 21, further comprising less than or equal to 1,000 parts per million of a substituted or an unsubstituted phenolphthalein relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 23. A 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprising less than or equal to 1,000 parts per million of 2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine, relative to an overall weight of said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
 24. The 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine of claim 23, further comprising less than or equal to about 1000 parts per million of phenolphthalein relative to an overall weight of said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
 25. A polymer composition comprising structural units derived from the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine of claim
 21. 26. A polymer composition comprising structural units derived from the 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine of claim
 23. 27. The polymer composition of claim 26, wherein said polymer is selected from the group consisting of homopolymers and copolymers of a polycarbonate, a polyestercarbonate, a polyester, a polyesteramide, a polyimide, a polyetherimide, a polyamideimide, a polyether, a polyethersulfone, a polycarbonate-polyorganosiloxane block copolymer, a copolymer comprising aromatic ester, estercarbonate, and carbonate repeat units; and a polyetherketone.
 28. A polymer blend comprising at least one thermoplastic polymer and the polycarbonate of claim
 27. 29. The polymer blend of claim 28, wherein said at least one thermoplastic polymer is selected from the group consisting of vinyl polymers, acrylic polymers, polyacrylonitrile, polystyrenes, polyolefins, polyesters, polyurethanes, polyamides, polysulfones, polyimides, polyetherimides, polyphenylene ethers, polyphenylene sulfides, polyether ketones, polyether ether ketones, ABS resins, polyethersulfones, poly(alkenylaromatic) polymers, polybutadiene, polyacetals, polycarbonates, polyphenylene ethers, ethylene-vinyl acetate copolymers, polyvinyl acetate, liquid crystal polymers, ethylene-tetrafluoroethylene copolymer, aromatic polyesters, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene chloride, tetrafluoroethylene, polycarbonate - polyorganosiloxane block copolymers, copolymers comprising aromatic ester, estercarbonate, and carbonate repeat units mixtures; and blends comprising at least one of the foregoing polymers.
 30. An article comprising the polymer composition of claim
 25. 31. An article comprising the polymer composition of claim
 26. 32. A method for producing a polycarbonate comprising structural units derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine impurity relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the method is selected from the group consisting of a melt transesterification polymerization method, and an interfacial polymerization method.
 33. The method of claim 32, wherein said melt transesterification polymerization comprises: forming a reaction mixture comprising a catalyst and a reactant composition, wherein the reactant composition comprises a carbonic acid diester and the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, wherein the carbonic acid diester is of the formula (ZO)₂C═O, where each Z is independently an unsubstituted or a substituted alkyl radical, or an unsubstituted or a substituted aryl radical; and mixing the reaction mixture under reactive conditions for a time effective to produce a polycarbonate product.
 34. The method of claim 33, wherein said carbonic acid diester comprises an activated aromatic carbonate having the formula:

wherein Q and Q′ are each independently activating groups selected from the group of radicals consisting of (alkoxycarbonyl)aryl groups, halogens, nitro groups, amide groups, sulfone groups, sulfoxide groups, or imine groups with structures:

wherein X comprises halogen or NO₂, M and M′ independently comprises N-alkyl, N-aryl, or N-alkyl aryl; R⁴ comprises alkyl or aryl; A and A′ are each independently aromatic rings; a and a′ can be zero to whole numbers of up to a maximum equivalent to the number of replaceable hydrogen groups substituted on the aromatic rings A and A′ respectively, provided a+a′ is greater than or equal to 1; R and R′ are each independently substituent groups selected from the group consisting of alkyl, cycloalkyl, alkoxy, aryl, cyano, nitro, and halogen; b is zero to a whole number up to a maximum equivalent to the number of replaceable hydrogen groups on the aromatic ring A minus a; and b′ is zero to a whole number up to a maximum equivalent to the number of replaceable hydrogen groups on the aromatic ring A′ minus a′.
 35. The method of claim 33, wherein the carbonic acid diester is an ester-substituted diaryl carbonate of formula:

wherein R⁵ is independently at each occurrence selected from the group consisting of an C₁-C₂₀ alkyl radical, a C₄-C₂₀ cycloalkyl radical, and a C₄-C₂₀ aromatic radical; R⁶ is independently at each occurrence selected from the group consisting of a halogen, a cyano group, a nitro group, a C₁-C₂₀ alkyl radical, a C₄-C₂₀ cycloalkyl radical, a C₄-C₂₀ aromatic radical, a C₁-C₂₀ alkoxy radical, a C₄-C₂₀ cycloalkoxy radical, a C₄-C₂₀ aryloxy radical, a C₁-C₂₀ alkylthio radical, a C₄-C₂₀ cycloalkylthio radical, a C₄-C₂₀ arylthio radical, a C₁-C₂₀ alkylsulfinyl radical, a C₄-C₂₀ cycloalkylsulfinyl radical, a C₄-C₂₀ arylsulfinyl radical, a C₁-C₂₀ alkylsulfonyl radical, a C₄-C₂₀ cycloalkylsulfonyl radical, a C₄-C₂₀ arylsulfonyl radical, a C₁-C₂₀ alkoxycarbonyl radical, a C₄-C₂₀ cycloalkoxycarbonyl radical, a C₄-C₂₀ aryloxycarbonyl radical, a C₂-C₆₀ alkylamino radical, a C₆-C₆₀ cycloalkylamino radical, a C₅-C₆₀ arylamino radical, a C₁-C₄₀ alkylaminocarbonyl radical, a C₄-C₄₀ cycloalkylaminocarbonyl radical, a C₄-C₄₀ arylaminocarbonyl radical, and a C₁-C₂₀ acylamino radical; and c is independently at each occurrence is zero to a whole number to
 4. 36. The method of claim 33, wherein the carbonic acid diester is a bismethylsalicyl carbonate.
 37. The method of claim 33, wherein the reactive conditions comprises mixing the reactant mixture at a temperature and a pressure that are stepwise raised from a first step comprising a melting temperature of about 190° C. and a first pressure; a second step of about 190° C. to about 210° C. at a second pressure; a third step of about 210° C. to about 310° C. at a third pressure; and a fourth step of about 310° C. at a fourth pressure.
 38. The method of claim 37, wherein said first pressure is at about ambient pressure, second pressure is at about an ambient pressure to about 100 millibars, said third pressure is at about 100 millibars to less than or equal to about 1 millibar, and said fourth pressure is at less than or equal to about 1 millibar.
 39. The method of claim 33, wherein said reactant composition further comprises at least one aromatic dihydroxy compound of the formula:

wherein each G¹ is an independently aromatic group; E is selected from the group consisting of an alkylene group, an alkylidene group, a cycloaliphatic group, a sulfur-containing linkage group, a phosphorus-containing linkage group, an ether linkage group, a carbonyl group, a tertiary nitrogen group, and a silicon-containing linkage group; R³ is a hydrogen or a monovalent hydrocarbon group each; Y¹ is independently selected from the groups consisting of a monovalent hydrocarbyl group, an alkenyl group, an allyl group, a halogen, an oxy group and a nitro group; each m is independently a whole number from zero through the number of positions on each respective G¹ available for substitution; p is a whole number from zero through the number of positions on E available for substitution; t is a natural number greater than or equal to one; s is either zero or one; and u is a whole number.
 40. The method of claim 39, wherein the at least one aromatic dihydroxy compound is selected from the group consisting of 4,4′-(3,3,5-trimethylcyclohexylidene)diphenol, 4,4′-bis(3,5-dimethyl)diphenol, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4′-hydroxy-3 ′methylphenyl)cyclohexane, 4,4′-[1-methyl-4-( 1-methylethyl)-1,3-cyclohexandiyl]bisphenol, 4-[1-[3-(4-hydroxphenyl)-4methylcyclohexyl]1-methyl-ethyl]-phenol, 3,8-dihydroxy-5a, 10 b-diphenylcoumarano-2′,3′,2,3-coumarane, 2-phenyl-3 ,3-bis(4-hydroxyphenyl)phthalimidine, 4,4-bis(4-hydroxyphenyl)heptane, 2,4′-dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, bis(4-hydroxy-2,6-demethyl-3-methoxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-2-chlorophenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-ethylphenyl)propane, 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane, bis(4-hydroxyphenyl)cyclohexylmethane, 2,2-bis(4-hydroxyphenyl)-1-phenylpropane, 2,4′-dihydroxyphenyl sulfone, 4,4′-dihydroxydiphenylsulfone, 9,9-bis(4-hydroxyphenyl)fluorene, 4,4′dihydroxy-1,,1-biphenyl, 2,6-dihydroxy naphthalene; hydroquinone; resorcinol, C₁₋₃ alkyl-substituted resorcinols, 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol, 1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol, and 2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl-1,1′-spirobi[1H-indened]-6,6′-diol.
 41. The method of claim 33, wherein the catalyst comprises: an alpha catalyst selected from the group consisting of alkali metal salts and alkaline earth metal salts; and a beta catalyst selected from the group consisting of a quaternary ammonium compound and a quaternary phosphonium compound.
 42. The method of claim 32, wherein said interfacial polymerization comprises reacting in a two-phase medium, a monomer mixture comprising said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine and phosgene in the presence of an acid acceptor and an aqueous base to produce said polycarbonate.
 43. The method of claim 42, wherein said polycarbonate has a weight average molecular weight from about 40,000 Daltons to about 75,000 Daltons, relative to a polystyrene standard.
 44. An article comprising the polycarbonate prepared in accordance with the method of claim
 42. 45. The article of claim 44, wherein said article has a yellowness index of less than or equal to about 10, as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 46. The method of claim 32, wherein said interfacial polymerization method comprises: reacting phosgene with a monomer mixture comprising said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in an organic solvent to form a 2-hydrocarbyl-3,3-bis{(4-chloroformyl)aryl}phthalimidine; and reacting said 2-hydrocarbyl-3,3-bis{(4-chloroformyl)aryl}phthalimidine with an aromatic dihydroxy compound or said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine in the presence of an acid acceptor and an aqueous base.
 47. The method of claim 32, wherein said interfacial polymerization method comprises: introducing into a tubular reactor system phosgene, at least one solvent, at least one bisphenol, caustic, and optionally one or more catalysts, thereby forming a flowing reaction mixture; passing said flowing reaction mixture through said tubular reactor system until substantially all of the phosgene has been consumed; introducing into said flowing reaction mixture in which substantially all of the phosgene has been consumed, caustic, at least one end-capping agent, and at least one catalyst to form an end-capped polycarbonate; and removing said end-capped polycarbonate from said reactor system.
 48. A melt transesterification polymerization method comprising: combining a catalyst and a reactant composition to form a reaction mixture, wherein the reactant composition comprises a carbonic acid diester, a 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, and at least one aromatic dihydroxy compound comonomer, wherein the carbonic acid diester is of the formula (ZO)₂C═O, wherein each Z is independently an unsubstituted or substituted alkyl radical, or an unsubstituted or substituted aryl radical, and, wherein said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine comprises less than or equal to 1,000 parts per million of 2-phenyl-3-{(4-hydroxyphenyl)(2-hydroxyphenyl)}phthalimidine relative to an overall weight of said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine; and mixing the reaction mixture under reactive conditions for a time period to produce a polycarbonate product.
 49. The method of claim 48, wherein said carbonic acid diester comprises diphenyl carbonate or bismethylsalicyl carbonate.
 50. The method of claim 48, wherein said at least one aromatic dihydroxy compound is selected from the group consisting of 4,4′-(3,3,5-trimethylcyclohexylidene)diphenol, 4,4′-bis(3,5-dimethyl)diphenol, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 4,4-bis(4-hydroxyphenyl)heptane, 2,4′-dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-2-chlorophenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-ethylphenyl)propane, 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane, bis(4-hydroxyphenyl)cyclohexylmethane, 2,2-bis(4-hydroxyphenyl)-1-phenylpropane, 2,4′-dihydroxyphenyl sulfone, 2,6-dihydroxy naphthalene, hydroquinone, C₁₋₃ alkyl-substitued resorcinaols, 3-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol, and 1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5ol, 2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl-1,1′-spirobi [1H-indene]-6,6′-diol, resorcinol, 4,4′-(1-decylinden)-bisphenol, 2,2-bis(3-sec-butyl-4-hydroxyphenyl)propane, and combinations comprising at least one of the foregoing aromatic dihydroxy compounds.
 51. The method of claim 48, wherein said at least one aromatic dihydroxy compound comonomer is bisphenol A.
 52. The method of claim 48, wherein said catalyst composition is 1×10⁻⁷ to about 2×10⁻³ moles for each mole of said reactant composition.
 53. The method of claim 48, wherein the reaction conditions comprises mixing said reaction mixture at a temperature that is stepwise raised from a first step comprising a melting temperature of about 180° C.; a second step of about 180° C. to about 230° C.; a third step of about 230° C. to about 270° C.; and a fourth step of about 270 ° C. to about 320 ° C.
 54. The method of claim 48, wherein said carbonic acid diester comprises a mole ratio of about 0.8 to about 1.30 relative to a total amount of moles of said 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine and said at least one aromatic dihydroxy compound comonomer.
 55. The method of claim 48, wherein said reactant composition further comprises 1,4:3,6-dianhydo-D-glucitol.
 56. A polycarbonate, comprising: structural units of formula derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen; and further wherein the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine.
 57. The polycarbonate of claim 56, further comprising structural units derived from at least one aromatic dihydroxy compound of the formula:

wherein each G¹ is an independently aromatic group; E is selected from the group consisting of an alkylene group, an alkylidene group, a cycloaliphatic group, a sulfur-containing linkage group, a phosphorus-containing linkage group, an ether linkage group, a carbonyl group, a tertiary nitrogen group, and a silicon-containing linkage group; R³ is a hydrogen or a monovalent hydrocarbyl group each; Y¹ is independently selected from the groups consisting of a monovalent hydrocarbon group, an alkenyl group, an allyl group, a halogen, an oxy group and a nitro group; each m is independently a whole number from zero through the number of positions on each respective G¹ available for substitution; p is a whole number from zero through the number of positions on E available for substitution; t is a natural number greater than or equal to one; s is either zero or one; and u is a whole number.
 58. The polycarbonate of claim 57, wherein the at least one aromatic dihydroxy compound is selected from the group consisting of 4,4′-(3,3,5-trimethylcyclohexylidene)diphenol, 4,4′-bis(3,5-dimethyl)diphenol, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4′-hydroxy-3′methylphenyl)cyclohexane, 4,4′-[1-methyl-4-(1-methylethyl)-1,3-cyclohexandiyl]bisphenol, 4-[1[3-(4-hydroxyphenyl)-4-methyl-ethyl]-phenol, 3,8-dihydroxy-5a, 10 b-diphenylcoumarano-2′,3′,2,3-coumarane, 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine, 4,4-bis(4-hydroxyphenyl)heptane, 2,4′-dihydroxydiphenylmethane, bis(2-hydroxyphenyl)methane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxy-2-chlorophenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-phenyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3-ethylphenyl)propane, 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(3,5,3′,5′-tetrachloro-4,4′-dihydroxyphenyl)propane, bis(4-hydroxyphenyl)cyclohexylmethane, 2,2-bis(4-hydroxyphenyl)-1-phenylpropane, 2,4′-dihydroxyphenyl sulfone, 4,4′-dihydroxydiphenylsulfone, 9,9-bis(4-hydroxyphenyl)fluorene, 4,4′dihydroxy-1,1-biphenyl, 2,6-dihydroxy naphthalene; hydroquinone; resorcinol, C₁-3alkyl-substituted resorcinols, 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol, 1-(4-hydroxyphenyl)-1,3,3-trimethylindan-5-ol, and 2,2,2′,2′-tetrahydro-3,3,3′,3′-tetramethyl-1,1′-spirobi[1H-indene]-6,6′-diol.
 59. The polycarbonate of claim 56, wherein said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine is 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine.
 60. The polycarbonate of claim 56, further comprising at least one end group derived from said activated carbonate.
 61. The polycarbonate of claim 60, wherein said at least one end group indicative of said activated carbonate has a structure of formula:

wherein Q is an ortho-positioned activating group; A is an aromatic ring, n is a natural numbers of 1 to the number of replaceable hydrogen groups substituted on the aromatic ring A; R₁ is a substituent group selected from the group consisting of alkyl, cycloalkyl, alkoxy, aryl, cyano, nitro, and halogen; b is a whole number of from 0 to the number of replaceable hydrogen groups on the aromatic ring minus n; and Q is a radical independently selected from the group consisting of (alkoxycarbonyl)aryl groups, halogens, nitro groups, amide groups, sulfone groups, sulfoxide groups, or imine groups with structures

wherein X comprises halogen or NO₂, M and M′ independently comprises N-alkyl, N-aryl, or N-alkyl aryl; R⁴ comprises alkyl or aryl when n is 1; and n has a value of 0 or
 1. 62. The polycarbonate of claim 60, wherein said end groups indicative of said activated carbonate comprise end groups has a structure of formula:

wherein R⁷ is a halogen atom, cyano group, nitro group, C₁-C₂₀ alkyl radical, C₄-C₂₀ cycloalkyl radical, C₄-C₂₀ aromatic radical, C₁-C₂₀ alkoxy radical, C₄-C₂₀ cycloalkoxy radical, C₄-C₂₀ aryloxy radical, C₁-C₂₀ alkylthio radical, C₄-C₂₀ cycloalkylthio radical, C₄-C₂₀ arylthio radical, C₁-C₂₀ alkylsulfinyl radical, C₄-C₂₀ cycloalkylsulfinyl radical, C₄-C₂₀ arylsulfinyl radical, C₁-C₂₀ alkylsulfonyl radical, C₄-C₂₀ cycloalkylsulfonyl radical, C₄-C₂₀ arylsulfonyl radical, C₁-C₂₀ alkoxycarbonyl radical, C₄-C₂₀ cycloalkoxycarbonyl radical, C₄-C₂₀ aryloxycarbonyl radical, C₂-C₆₀ alkylamino radical, C₆-C₆₀ cycloalkylamino radical, C₅-C₆₀ arylamino radical, C₁-C₄₀ alkylaminocarbonyl radical, C₄-C₄₀ cycloalkylaminocarbonyl radical, C₄-C₄₀ arylaminocarbonyl radical, or C₁-C₂₀ acylamino radical; and c is a whole number of 1-4.
 63. The polycarbonate of claim 60, wherein said end groups indicative of said activated carbonate comprises a structure having a formula:


64. The polycarbonate of claim 56, further comprising at least one internal ester-carbonate structural unit derived from said activated carbonate, having a formula:

wherein R⁷ is a halogen atom, cyano group, nitro group, C₁-C₂₀ alkyl radical, C₄-C₂₀ cycloalkyl radical, C₄-C₂₀ aromatic radical, C₁-C₂₀ alkoxy radical, C₄-C₂₀ cycloalkoxy radical, C₄-C₂₀ aryloxy radical, C₁-C₂₀ alkylthio radical, C₄-C₂₀ cycloalkylthio radical, C₄-C₂₀ arylthio radical, C₁-C₂₀ alkylsulfinyl radical, C₄-C₂₀ cycloalkylsulfinyl radical, C₄-C₂₀ arylsulfinyl radical, C₁-C₂₀ alkylsulfonyl radical, C₄-C₂₀ cycloalkylsulfonyl radical, C₄-C₂₀ arylsulfonyl radical, C₁-C₂₀ alkoxycarbonyl radical, C₄-C₂₀ cycloalkoxycarbonyl radical, C₄-C₂₀ aryloxycarbonyl radical, C₂-C₆₀ alkylamino radical, C₆-C₆₀ cycloalkylamino radical, C₅-C₆₀ arylamino radical, C₁-C₄₀ alkylaminocarbonyl radical, C₄-C₄₀ cycloalkylaminocarbonyl radical, C₄-C₄₀ arylaminocarbonyl radical, or C₁-C₂₀ acylamino radical; and c is a whole number of 1-4.
 65. The polycarbonate of claim 56, wherein said polycarbonate has a yellowness index of less than or equal to about 10, as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 66. An article comprising the composition of claim
 56. 67. The article of claim 66, wherein said article has a yellowness index of less than or equal to about 10, as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 68. The article of claim 66, wherein said article has a yellowness index of less than or equal to about 2, as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 69. The article of claim 66, comprising a film, a molded article, an automotive headlamp inner lens, an automotive headlamp outer lens, an automotive fog lamp lens, an automotive bezel, a medical device, a display device, an electrical connector, an under the hood automotive part, or a projector lens.
 70. A lens comprising a polycarbonate, wherein the polycarbonate comprises: structural units of formula derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen; and further wherein the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimi dine comprises less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; and a yellowness index of less than 10 as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 71. The lens of claim 70, wherein said polycarbonate comprises a yellowness index of less than 2 as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 72. A polycarbonate copolymer comprising structural units of formula derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen; and further wherein the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine comprises less than or equal to 1,000 parts per million of a 2-hydrocarbyl-3-{(4-hydroxyaryl)(2-hydroxyaryl)}phthalimidine relative to an overall weight of said 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine; wherein said polycarbonate copolymer has a yellowness index of less than 10 as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 73. The polycarbonate copolymer of claim 72, wherein said polycarbonate copolymer has a yellowness index of less than 10 as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 74. A polycarbonate copolymer comprising structural units of formula derived from a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine:

wherein R¹ is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R² is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen, wherein the polycarbonate copolymer has a yellowness index of less than 10 as measured on a 3 millimeter thick plaque in accordance with ASTM D1925.
 75. The polycarbonate copolymer of claim 74, wherein said polycarbonate as a yellowness index of less than 2 as measured on a 3 millimeter thick cordance with ASTM D1925. 